Datasheet

The SRC4190, SRC4192, and SRC4193
1-2
1.1 The SRC4190, SRC4192, and SRC4193
The SRC4192 and SRC4193 are stereo asynchronous sample rate convert-
ers designed for professional and broadcast audio applications. Operation at
input and output sampling frequencies up to 212kHz is supported, with an in-
put/output sampling ratio range of 16:1 to 1:16. Excellent dynamic range and
THD+N are achieved by employing high performance, linear phase digital fil-
tering with better than 140dB of image rejection. The SRC4190 is a lower–cost
version of the SRC4192 with reduced performance specifications, but it is
functionally equivalent to the SRC4192 and shares the same pin configura-
tion.
The SRC4190 and SRC4192 are both stand–alone, pin–programmed de-
vices, with control inputs for mode, data format, mute, bypass, and low group
delay functions. The SRC4193 includes a three–wire serial peripheral inter-
face (SPI) port, which allows access to on–chip control registers for device
function configuration. The SPI port can be easily interfaced to microproces-
sors or digital signal processors with synchronous serial port interfaces.
All three devices offer filtering options, which allow for lower group delay proc-
essing. These options include a low group delay mode for the interpolation
function and a direct down–sampling mode (SRC4193 only) for the decimation
function.
The audio input and output ports support standard audio data formats, as well
as a TDM interface mode. Word lengths of 24–, 20–, 18–, and 16–bits are sup-
ported. Both ports may operate in Slave mode, deriving their word (LRCK) and
bit (BCK) clocks from external input and output devices. Alternatively, one port
may be operated in Master mode while the other remains in Slave mode. In
Master mode, the LRCK and BCK clocks are derived from the reference clock
(RCKI) input. The flexible configuration of the audio ports allows connection
to a wide variety of audio data converters, digital audio interface devices, and
digital signal processors.
A bypass mode is also included. This mode allows data to be passed directly
from the audio input port to the audio output port, bypassing the sample rate
converter function. The bypass option is useful for passing through encoded
or compressed audio data, or non–audio control and status data. The input
and output port clocks must be synchronous with one another in bypass mode.
A soft mute function is included in all three devices. A digital attenuation func-
tion is available only for the SRC4193. Both soft mute and digital attenuation
functions provide artifact free operation, while allowing muting or level adjust-
ment of the audio output signal. The mute attenuation is typically –144dB for
the SRC4192 and SRC4193, and –128dB for the SRC4190. The SRC4193
digital attenuation function is adjustable from 0dB to –127.5dB in 0.5dB steps.
A block diagram of the SRC4192 and SRC4193 is shown in Figure 1–1. The
SRC4190 offers the same functionality as the SRC4192.